An aircraft fuselage is configured by having panels affixed to a frame. The panels are curved panels that follow the shape of the aircraft. The curved panels are secured to the frame using rivets. A relationship between the curved panels and the rivets is described in FIGS. 11A and 11B hereof.
Arivet hole 102 is formed in a curved panel 101, and a rivet 103 is driven into the rivet hole 102, as shown in FIG. 11A. An external peripheral end portion 104 (triangular portion shown by an imaginary line) of the head of the rivet 103 inevitably protrudes to the outside. In view of the above, the end portions 104, 105 are eliminated by shaving. As a result, the head of the rivet 103 becomes rounded, and air resistance can be reduced.
The distal end of a drill may slide and become misaligned when the drill is placed on the curved surface, and the rivet hole 102 may be formed diagonally. When this occurs, an axis 106 of the rivet 103 tilts at angle θ in relation to a normal 107 to the curved surface 101, as shown in FIG. 11B. As a result, the external peripheral end portion 104 protrudes considerably, the amount of cutting increases, and shaving costs increase. Also, the fastening performance of the rivet 103 is affected. In the case of FIG. 11A, there is no problem because the angle θ is zero or sufficiently small. Accordingly, there is a need for a technique that can reduce the angle θ.
In this manner, a drill guide jig is known that can reduce the tilting angle θ of the rivet 103, as disclosed in Japanese Patent Application Laid-Open Publication No. 2003-39217, for example. The fixed jig disclosed in the 2003-39217 publication is shown in FIGS. 12A to 12C hereof.
A fixed jig 110 used for securing a workpiece is composed of support stands 111, 111, support columns 112, 112 supported by the support stands 111, 111, a workbench 113 supported by the support columns 112, 112, and a plurality of jig parts 114 disposed on the workbench 113, as shown in FIG. 12A.
A fixed part 116 manufactured so as to conform to the shape of a first workpiece 115 on the lower surface of the workpiece 115, a second workpiece 117 fastened by a rivet to the first workpiece 115, and a main jig unit 119 having a guide hole 118 for holding a drill are disposed in the jig parts 114, as shown in FIG. 12B, which is an enlarged view of b of FIG. 12A. The main jig body 119 is supported by a plurality of support grooves 121 formed on the fixed part 116.
The main jig body 119 is composed of a base 123 having a protruding part 122 that fits into a support groove 121 (FIG. 12B) at the end part, a spherical bearing 124 inserted into the base 123, and a guide bush 125 inserted into the spherical bearing 124 and which guides the drill, as shown in FIG. 12C, which is an enlarged view of c of FIG. 12B.
The guide bush 125 slides due to the action of the spherical bearing 124, and a guide hole 118 is positioned in relation to the first workpiece 115 when the distal end of the guide bush 125 is brought into contact with the first workpiece 115 (FIG. 12B).
With the fixed jig 110, a rivet hole can be formed at a prescribed angle by inserting the drill through the guide hole 118. It is beneficial that a rivet hole can be formed at a prescribed angle, regardless of the ability of a worker.
However, the fixed jig 110 must be provided with jig parts 114 in accordance with the number of rivet holes. The fixed part 116, which is an essential part in the jig parts 114, is very expensive due to being manufactured each time in accordance with the shape of the first workpiece 115. Additionally, the spherical bearing 124, which a part essential to the jig parts 114, has a complex mechanism and is very expensive. When the number of rivet holes to be formed increases, the number of jig parts 114 also increases and manufacturing costs increase as well.